Bird 1.6.3 cycle-restarting with SegFault during load-testing

[David.Garay at os3.nl]

Dear all, good afternoon

New user, excuses in advance if the question has been answered elsewhere 
- despite not having found anything on the mailing list history.

For my Master thesis, I am investigating the impact of configuration 
changes resulting from IRRDB updates on route server infrastructure. 
During my experiments I got a segfault from Bird, and wanted to ask a 
few questions about it.

The details of the problem are below. Please let me know if you miss 
anything, and thank you in advance,

David


** Problem description:
For load testing, I am having my Bird route server instance peer with 
other 1100 peers (containers, basic bgp config).

CPU utilization and Memory are normal (~5%/30% respectively) and I see 
BGP session establishments go above 1000 sessions without problems, but 
at 1013 consistently Bird raises seg-fault and restarts.

Output shows:

2019-06-27 12:37:49 <ERR> BGP: Error on listening socket: Too many open 
files

Which seem to be related to dynamic buffers running out due to BGP open 
sessions.

Bird version: 1.6.3
CPU details: Intel(R) Xeon(R) CPU E3-1220L V2 @ 2.30GHz, 4 cores).


** Actions taken:
- Resource dump available, also: repeated tests to verify the restart 
always happen at 1013 bgp sessions.

** Questions:
- Is the issue I just described known?
- Are there (known) hard-coded limits on Bird? What is the expected 
behaviour under these conditions?
- In general, what are other dimensioning variables to be taken into 
account with Bird?

** Logs:
Zip file containing: resource dump, count of bgp sessions, further 
analysis.
https://we.tl/t-mRmgIgC38a